Method of molding joints between spaced structural members



April 17, 1951 K. P. BILLNER 2,548,935

METHOD OF MOLDING JOINTS BETWEEN SPACED STRUCTURAL MEMBERS Filed Sept.5,-1.947 I 2 Sheets-Sheet 1 To Vacuum Pumr To Vacuum PUMP ToVncuum PM.511

H3 VACUUM PUMP. INVENTOR- Kmnu i=1 En LLN ER,

April 17, 1951 K. P. BILLNER 8,

METHOD OF MOLDING JOINTS BETWEEN SPACED STRUCTURAL MEMBERS 2Sheets-Sheet 2 Filed Sept. 5, 1947 INVENTOR.

Patented Apr. 17, 1951 TENT OFFICE METHOD OF MOLDING JOINTS BETWEEN iSPACED STRUCTURAL MEMBERS Karl P. Billner, Philadelphia, Pa., assignor qto Vacuum Concrete, Inc., a corporation of Pennsylvania ApplicationSeptember 1947 ,-'Serial No. 772,324

Claims. 1

Whereas precast .concrete techniques have obviated the need for much oftheform-work required where concrete is castin situ, current practicestill requires the site erection of forms for perfecting the jointsbetween such precast members. Inasmuch as the material andlabor requiredin the construction of forms represents an appreciable portion of thetotal cost of concrete work, it will be apparent thatthe use ofprefabricated joint forms which are rapidly applicable to and removablefrom the structure and capable ofrepeated use, will effect tremendousthe application of subatmospheric pressure to the plastic compositionitselffor the purpose of removing such excess vehicle as water, toproduce a more compactsolidified body in much shorter time than-would-bepossible under natural atmospheric conditions.

According to themethod of the present invention for forming a. jointbetween spaced structural members, such members are bridged with aclosure which is secured to at least one of them .by the application ofsubatmospheric pressure, and a plastic composition deposited-between the.members and the closure. the composition may be subjected to-subatmoS-'pheric pressure as well. It is-also contemplated As already indicated,

that opposed closures be thus employedto bridge the structural membersand that such closures be secured toat least one of the structuralmembers. The application of subatmospheric pressure to the compositionmay be produced through the closure or closures, by providing them witha perforated or-foraminoussurface for contact with the composition,which may beaccomplished-by covering the open side of an otherwiseclosedmat with a fabric permitting the passageof a vehicle such as Waterwhileserving as a barrier to solid particles of the sizes employed inthe composition.

As-previouslyi set forth by .the present inventor, a substantial portionof the water addedin the production of a concrete mix forcommercial useserves the solev purposepf producing workable consistencies andrepresents an excess insofar as the requirements for setting areconcerned. It is this excess vehicle, or a substantial portion thereofwhich can be removed to advantage after the. concrete mix has beendeposited, to produce structures which become self supporting soon afterdeposition and which possess superior characteristics of compactness,strength, impact resistance and uniformity, as compared with concretestructures produced by more commonly known commercial methods.

The apparatus contemplated herein for. casting a moldable plasticcomposition between spaced structural members, comprises a moldingsurface for contact with the composition, sealing means on the surfacefor engagement with a surface portion of the members, holding meansconnected with the molding surface comprising a mat having sealing meansfor engagement with an adjacent surface portion of the members, andmeans for applying subatmospherie pressure intermediate the holdingmeans and the adjacent surface portion. It is also intended that meansfor applying subatmospheric pressure between the molding surface and thecomposition be provided. A- perforate molding surface of the typehereinabove mentioned and describedv elsewhere amongiapplicants patentsand applications, may assume the form of a fabric covering for the openside of an otherwise closed mat, supported with respect to the mat byspacing means such as wire mesh or other suitable material.

The holding meansmay comprise a plurality of-matsto besecured to thestructural members adjacent themolding surface. Marginal sealing meanson the moldingsurface may engage adja cent-surfaces of the structuralmembers and provide a seal between the molding surface and the holdingmeans as well as between the composition and-atmosphere. The holdingmeans may Ice-integral with or separable from themolding surface and theholding means may provide por- 'tions overhanging the molding surface toserve :as a bearing for properly fixing the molding surface during themoldingoperation.

' I-t'has been found'in actual practice withthe apparatus of the presentinvention, that shortly after the subatmospheric pressure-has beenapplied to the composition, the separable holding means 'can'be removed,since the composition will become self-supporting so-rapidly after aportion-of the excess vehicle has been removed that the static forcestending to displace the molding surfaceare rapidly and a'opreciablyreduced. And as amatterof fact. the time required .for retainingthemolding surface-itself-in position is diminished to a relativelyshort period becauseof the rapidity with which the composition becomesself supporting under the influence of the subatmospheric pressure toremove the excess water.

A more complete understanding of the invention will follow from adetailed description based upon the accompanying drawings wherein:

Fig. 1 is a fragmentary perspective illustrating the invention asapplied to wall construction;

Fig. 2 is a fragmentary section taken along the line 22 of Fig. 1;

Fig. 3 is an elevation of one of the forms shown at the right of Fig. 1;and

Fig. 4 is a section taken along line 44 of Fig. 3.

The precast concrete wall members H! and I2 define a corner of thestructure under consideration and an adjacent structural member l4coplanar with one of the corner forming members [2 cooperates in forminga portion of one of the walls. An external closure 161 is shown asbridging the corner forming members, retained in posotion by a holder [8applied to a portion of the member in and a holder 20 applied to a.portion of the member l2. An internal corner closure 22 is similarlypositioned to bridge the corner forming members by a holder 24 appliedto a portion of the member Ill and a holder 26 applied to a portion ofthe member I2. These corner closures are depicted as separable fromtheir respective holders while the closures 28 employed for producingthe running joint between the elements [2 and 14 have been illustratedas unitary with their holders 30, and applied to opposite surfaceportions of the spaced elements I 2 and I 4.

Each of the holders is provided with marginal sealing means 32 toexclude atmosphere when it defines a closed chamber with the surface ofthe structural member to which it is applied for producing therein asubatmospheric pressure through i a line 34 communicating with asuitable source of such pressure, such as a vacuum pump.

Each of the closure members is likewise illustrated as havingcommunication with a source of subatmospheric pressure through a line 36for ner joint or column is illustrated in more detail in Fig. 2 whereinthe precast structural members 10 and I2 are shown as having enlargedends 38 containing grooves 40 with which the deposited concrete 42 willbecome interlocked. The closure member It may be formed from twosections of plywood or the like arranged at right angles and reinforcedby an angle M. The internal or molding surface of the closure I 6 isbounded by a sealing member 46 of strip rubber or the like which bearsupon the adjacent edge portions of the spaced precast structural membersbetween which the joint is to be produced. The portion of the closuremolding surface intermediate this marginal sealing means is faced with awoven fabric 48 pervious to wate or other vehicle to be withdrawn butimpervious to the solid particles of the composition being molded. Thefabric is supported out of contact with the closure body by means ofwoven wire mesh 50 or the like so that the subatmospheric pressureproduced through a projecting nipple 52, by means of a vacuum pumpconnected therewith by a conduit 36, will be substantially uniformlydistributed over the adjacent surfaceof the composition 42.

Since the concrete or other plastic composition is usually quite plasticwhen first deposited, its static head requires appreciable force forretention of the closures at the outset, produced in this case by theuse of vacuum operated holders. For this purpose the closures l8 and 20,which may be constructed of a suitable number of layers of plywood areapplied to portions of the structural members adjacent the closure bymeans of subatmospheric pressures produced through a suitable number ofnipples 54 and conduits 34 leading to a vacuum pump. The wall engagingsurfaces of these holders carry yieldable sealing members 58 formed ofsponge rubber or the like retained between suitable strips or beads 58.Similar sponge rubber supports 60 are provided intermediate the sealingmembers, particularly where the spans involved would otherwise produceexcessive stresses upon the holder body under the subatmosphericpressures encountered. To assure a quick and positive seal between theholders and the wall surfaces to which they are applied, even where suchsurfaces are somewhat rough, thin rubber sealing flaps 62 are secured tothe sealing members 56 to extend therebeyond for engagement with anappreciable area of the wall, which flaps may assume the form of limpresilient and thin material such as yellow balloon rubber. overhangingportions of these holders provide projections 64 which engage a portionof the closure to force it into its operative position when the holderis applied to the wall and its sponge rubber sealing members andsupports yield under the influence of the sub-atmospheric pressureproduced between the holder and the wall as shown in Fig. 2.

The internal corner closure 22 is likewise provided with a marginalrubber sealing gasket 46 and faced with a fabric backed with woven wiremesh or the like in the same manner as described with respect to theexternal closure. The internal holders 24 and 26 are inturn similar tothe external holders i8 and 20 except for such physical dimensions asmay vary to accommodate the configuration of particular structuralmembers. In the case illustrated in Fig. 2, the internal holders aresomewhat narrower and somewhat thicker than the external holders.

In applying the invention, with the structural members I 0 and H2 inerected position, the internal and external closures are applied, theseparable holders positioned to bear upon them, and subatmosphericpressure is then introduced between the holders and the structuralmembers through the conduits and nipples provided for this purpose. Thiswill result in securing the closures in position, whereupon the plasticmix is introduced into the form thus defined and subatmospheric pressureis applied to the mix through the perforate surfaces of one or both ofthe closures. As soon as a predetermined portion of the excess vehiclehas been withdrawn from the mix, the composition begins to become selfsupporting and the static head becomes reduced sufficiently to permitdiscontinuance of the subatmospheric pressures applied between theholders and the structural members and the holders themselves canthen beremoved. In due time, the subatmospheric pressure applied to thecomposition through the closure or closures can also be discontinued andthe closures removed.

In some instances, particularly where the thickness of the column orjoint is small, it may be unnecessary to apply subambient pressure bothinternally and externally of the concrete,

in which case one of the closures may serve merely as a barrier toretain the mix in position while the subatmospheric pressure is appliedto the opposite surface alone. In such a case, one of the closures mayassume a simpler form.

It will be understood that the running joints or columns may be producedwith similarly separable closures and holders, difiering inconfiguration to accommodate the shape which it is desired to impart tothe molded material. It is contemplated for some applications of theinvention, to construct the closures and holders in a unitary fashion,as distinguished from separably, as has been depicted in Figs. 3 and 4.In these figures, the closure 28 and the holders 30 are suitably joinedtogether by bolts, screws, or the like, so that the assembly may beapplied as a unit to the spaced structural members between which it isdesired to produce a molded joint. Inasmuch as the elements composingthis formof the invention are similar to those described with referenceto the preceding figures, they have been similarly identified and willrequire no extended discussion. It will be noted that the intermediatesupports 60 best shown in Fig. 3 can be terminated or extended asdesired to best suit the surface to which it is applied. It will beunderstood that the closures and holders for such running joints mightwell be separable in the manner described with reference to the cornerjoint previously described, bearing in mind that where the constructionis unitary, the entire assembly must be retained in position until thecomposition has become sufficiently self supporting to permit itsremoval.

The subatmospheric pressures applicable to the plastic composition willassume values in the ranges disclosed in the Billner Patent No. 2,046,-867, dated July 7, 1936, and the subatmospheric pressures applied to theholders will be as great or greater. The effective area of the holder orholders for a given closure opposed to a coopcrating surface will becomputed in each application to exceed that necessary to retain the formequipment and plastic composition in position for the valve ofsubatmospheric pressure to be used.

Whereas but two specific embodiments of the invention have beendescribed with reference to the drawings, many variations will occur tothose skilled in the art as they have been recognized already by thepresent inventor, rendering it important that these examples should notbe construed to restrict the invention beyond the scope of the appendedclaims.

I claim:

1. A method of forming a joint between spaced structural memberscomprising bridging said members with a closure, securing the closure influid tight relationship to at least one of said members by theapplication of subatmospheric pressure, and depositing a plasticcomposition between said members and closure.

2. A method of forming a joint between spaced structural memberscomprising bridging said members with a closure, securing the closure toat least one of said members by the application of subatmosphericpressure, depositing a plastic composition between said members andclosure, and subjecting said composition to subatmospheric pressure.

3. A method of forming a joint between spaced structural memberscomprising bridging said members with opposed closures, securing saidclosures in fluid tight relationship to at least one of said members bythe application of subatmospheric pressure, and depositing aplasticcomposition between said members and closures.

4. A method of forming a joint between spaced structural memberscomprising bridging said members with opposedclosures, securing at leastone of said closures in fluid tight relationship to at least one of saidmembers by the application of subatmospheric pressure and depositing aplastic composition between said members and closures.

5. A method of forming a joint between spaced structural memberscomprising bridging said members with opposed closures, securing saidclosures in fluid tight relationship to said members by the applicationof subatmospheric pressure, and depositing a plastic composition betweensaid members and closures.

- 6. A method of forming a joint between spaced structural memberscomprising bridging said members with a closure, securing the closuretoat least one of said members by the application of subatmosphericpressure, depositing a plastic composition between said members andclosure, and applying subatmospheric pressure to said compositionthrough said closure.

7. A method of forming a joint between spaced structural memberscomprising bridging said members with 'a closure, securing the closureto at least one of said members by the application of subatmosphericpressure, depositing a plastic composition containing excess vehiclebetween said members and closure, and removing a portion of said vehicleunder subatmospheric pressure conditions.

8. A method of formin a joint between spaced structural memberscomprising bridging said members with a closure, securing the closure influid tight relationship to said members by the application ofsubatmospheric pressure, and depositing a plastic composition betweensaid members and closure.

9. A method of forming a joint between spaced structural memberscomprising bridging said members with a closure, securing the closure tosaid members by the application of subatmospheric pressure, depositing aplastic composition between said members and closure, and applyingsubatmospheric pressure to said composition through said closure.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 882,196 Hahn Mar. 17, 1908958,419 Mowat May 17, 1910 1,500,121 Fontaine July 8, 1924 1,630,801Persons 1. 1 May 31, 1927 2,046,867 Billner July 7, 1936. 2,239,989Britten Apr. 29, 1941 2,317,997 Lapidus May 4, 1943 Billner June 28,1949

